Bulk tailings facility will require a liner. IMO:
Both acid generating AND bulk flotation tailings facilities' will require synthetic liners. Only the acid generating tailings facility is currently proposed to be lined. Operational and post-operational acid generating waste rock dump(s) will required full water management including a synthetic liner.
Lining of the bulk tailings facility will be required due to groundwater pump-back wells not being adequate/reliable/effective in ensuring groundwater quality protection during and after operations. Groundwater recharges surface water and as such surface water/fishery quality will need to meet an aquatic discharge standard at a minimum.
Lining of the the bulk tailings facility will require additional embankment stabilization in meeting dam safety requirements.
This project is a water management, treatment and discharge challenge during and after closure. The site will require "perpetual" water treatment due to open pit lake discharge.
Underground mining ONL6 while incorporating acidic waste rock and tailings backfilling.